Hydrolysis stabilizer for ester group-containing resin

ABSTRACT

A hydrolysis stabilizer for an ester group-containing resin, which comprises as a main component a carbodiimide having at least two carbodiimide groups in the molecule and resulting from 4,4&#39;-dicyclohexylmethane diisocyanate, isophorone diisocyanate or a mixture of 4,4&#39;-dicyclohexylmethane diisocyanate and isophorone diisocyanate, or from a mixture of tetramethylxylylene diisocyanate with 4,4&#39;-dicyclohexylmethane diisocyanate, isophorone diisocyanate or a mixture of 4,4&#39;-dicyclohexylmethane diisocyanate and isophorone diisocyanate; and a process for the hydrolysis stabilization of an ester group-containing resin, which comprises mixing a polyester type resin with the above hydrolysis stabilizer.

This application is a division of application Ser. No. 08/826,967, filed Apr. 9, 1997 now U.S. Pat. No. 5,889,096.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a hydrolysis stabilizer for an ester group-containing resin and a process for the hydrolysis stabilization of an ester group-containing resin using said hydrolysis stabilizer. More particularly, it relates to a hydrolysis stabilizer for an ester group-containing resin which stabilizer does not generate a bad odor when kneaded with the resin at a high temperature, has an excellent compatibility and reactivity with a resin to which the stabilizer is added, even at a low temperature and exhibits thereby an excellent hydrolysis stabilizing effect and comprises a carbodiimide as a main component, and to a process for the hydrolysis stabilization of an ester group-containing resin using the above hydrolysis stabilizer.

2. Description of Related Art

Ester group-containing resins (referred to hereinafter as ester type resins in some cases), for example, polyester polyurethane (PU), polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and the like have excellent elasticity and moldability, and hence, have been employed in various uses.

However, for example, the above-mentioned polyester polyurethane resin is usually obtained by urethanizing a diisocyanate such as 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI) or the like with a difunctional polyester polyol, so that it has many ester groups in the molecule. Accordingly, it is known that there are such problems that not only is this ester group easily hydrolyzed with moisture to cause reduction of molecular weight, but also the acidic carboxyl group formed by this hydrolysis accelerates the hydrolysis of the ester linkage, so that the strength is reduced and the reduction of strength makes it impossible for the resin per se to resist the strain caused during the curing of the resin, whereby cracking and further reduction of strength are caused.

In order to prevent such deterioration of physical properties, it has been tried to add various additives during the molding of a polyester polyurethane resin to trap the carboxyl groups and alcohol groups formed by the hydrolysis, thereby preventing hydrolysis from further proceeding.

The above additives include, for example, oxazolines, epoxy compounds, aromatic polycarbodiimides, aliphatic monocarbodiimides and the like. These additives are usually in the form of powder and used in such a manner that they are dry blended with resin pellets or mixed in a given amount with the resin by use of a measuring hopper during molding or spinning, and then, the resulting mixture is melt-kneaded at a given temperature (250-300° C. in the case of polyethylene terephthalate).

However, the above-mentioned epoxy compounds and oxazolines have no sufficient effect of improving the hydrolysis resistance, increase the melt viscosity of the resin and deteriorate the moldability, so that they have no practical usability. Moreover, the above aromatic carbodiimides are usually thermosetting, and hence, their carbodiimide groups cross-link upon heating and when they are kneaded with the resin, the viscosity of the resulting mixture increases or they become lump-like and are ununiformly dispersed in the resin, and hence, in some cases, no desirable effect of hydrolysis stabilization can be obtained.

For the purpose of preventing the above-mentioned problems of aromatic carbodiimides when heated, there have been developed various aromatic carbodiimides having a group of high steric hindrance in the ortho-position to the carbodiimide group. However, these aromatic carbodiimides are pyrolyzed by a heat applied when they are melt-kneaded with a polyester polyurethane resin, and in addition, generate remarkably unpleasant odor due to the vaporization of impurities or starting materials, resulting in a deterioration of working atmosphere. Furthermore, the gas generated contains aromatic amines and the like and hence is very dangerous in view of not only bad odor but also toxicity, and hence, there is such a problem that a large scale deodorizing or ventilating apparatus becomes necessary.

Moreover, as aliphatic carbodiimides, the use of dicyclohexylcarbodiimide is well known; however, this dicyclohexylcarbodiimide reacts easily with water to be converted to dicyclohexylurea, and hence, has a problem in that close attention must be paid for preventing moisture in the storage of dicylohexylcarbodiimide. Therefore, it is inadequate to use in industry. Furthermore, a monocarbodiimide is a low molecular weight compound and when added to a polyester polyurethane resin, it bleeds out of the resin, so that it has such a problem that the hydrolysis resistance is not sufficient.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the above disadvantages of the prior art and provide a hydrolysis stabilizer for an ester group-containing resin such as polyester polyurethane resin or the like which stabilizer has an excellent compatibility with said resin, can be easily added without any trouble to said resin during the synthesis and melt-kneading of said resin, has a high molecular weight and, therefore, can sufficiently exhibit the effect of hydrolysis stabilization of the said resin.

It is another object of the present invention to provide a process for the hydrolysis stabilizer of an ester group-containing resin using the above hydrolysis stabilizer.

According to the present invention, there is provided a hydrolysis stabilizer for an ester group-containing resin, which comprises as a main component a carbodiimide having at least two carbodiimide groups in the molecule and resulting from 4,4'-dicyclohexylmethane diisocyanate represented by the formula (I): ##STR1## or isophorone diisocyanate represented by the formula (II): ##STR2## or a mixture of 4,4'-dicyclohexylmethane diisocyanate of the formula (I) with isophorone diisocyanate of the formula (II), or, a carbodiimide having at least two carbodiiumide groups in the molecule and resulting from a mixture of tetramethylxylylene diisocyanate represented by the formula (III): ##STR3## with 4,4'-dicyclohexylmethane diisocyanate represented by the formula (I), isophorone diisocyanate represented by the formula (II) or a mixture of 4,4'-dicyclohexylmethane diisocyanate of the formula (I) and isophorone diisocyanate of the formula (II).

According to the present invention, there is further provided a process for the hydrolysis stabilization of an ester group-containing resin which comprises mixing a polyester resin with a carbodiimide having at least two carbodiimide groups in the molecule and resulting from 4,4'-dicyclohexylmethane diisocyanate represented by the formula (I): ##STR4## or isophorone diisocyanate represented by the formula (II): ##STR5## or a mixture of 4,4'-dicyclohexylmethane diisocyanate of the formula (I) with isophorone diisocyanate of the formula (II), or, a carbodiimide having at least two carbodiimide groups in the molecule and resulting from a mixture of tetramethylxylylene diisocyanate represented by the formula (III): ##STR6## with 4,4'-dicyclohexylmethane diisocyanate represented by the formula (I), isophorone diisocyanate represented by the formula (II) or with a mixture of 4,4'-dicyclohexylmethane diisocyanate of the formula (I) and isophorone diisocyanate of the formula (II).

DETAILED DESCRIPTION OF THE INVENTION

The present hydrolysis stabilizer for an ester group-containing resin comprises as a main component;

(1) a carbodiimide having at least two carbodiimide groups in the molecule and resulting from 4,4'-dicyclohexylmethane diisocyanate represented by the above formula (I) (referred to hereinafter as HMDI in some cases), or, isophorone diisocyanate represented by the above formula (II) (referred to hereinafter as IPDI in some cases), or, a mixture of HMDI and IPDI, or

(2) a carbodiimide having at least two carbodiimide groups in the molecule and resulting from a mixture of tetramethylxylylene diisocyanate represented by the above formula (III) (referred to hereinafter as TMXDI in some cases) with HMDI, IPDI or a mixture of HMDI and IPDI.

Said carbodiimide can be produced by subjecting (1) HMDI, IPDI or a mixture of HMDI and IPDI, or (2) a mixture of TMXDI with HMDI, IPDI or a mixture of HMDI and IPDI, as the starting materials to carbodiimidization reaction accompanied by decarboxylation reaction.

The above carbodiimidization reaction is effected in the presence of a suitable carbodiimidization catalyst, and as the carbodiimidization catalyst which can be used, organic phosphorus compounds are preferable, and phosphorene oxides are particularly preferable in view of activity. Specifically, there are mentioned 3-methyl-1-phenyl-2-phosphorene-1-oxide, 3-methyl-1-ethyl-2-phosphorene-1-oxide, 1,3-dimethyl-2-phosphorene-1-oxide, 1-phenyl-2-phosphorene-1-oxide, 1-ethyl-2-phosphorene-1-oxide, 1-methyl-2-phosphorene-1-oxide and double bond isomers thereof. Among them, 3-methyl-1-phenyl-2-phosphorene-1-oxide, which is easily commercially available, is particularly preferable.

The above carbodiimidization reaction can be carried out by a known method, for example, by adding the above-mentioned catalyst to (1) HMDI, IPDI or a mixture of HMDI and IPDI, or (2) a mixture of TMXDI with HMDI, IPDI or a mixture of HMDI and IPDI in the absence of a solvent or to a solution of (1) or (2) in a solvent inert thereto, in a proportion of 0.1 to 10% by weight (a larger amount is possible when the economy is neglected), preferably 0.5 to 5% by weight, based on the total weight of the isocyanates in the atmosphere of an inert gas such as nitrogen or the like or with bubbling of the inert gas, and then heating the resulting mixture with stirring at a reaction temperature within the range of from 150° C. to 200° C., thereby allowing a carbodiimidization reaction accompanied by decarboxylation reaction to proceed.

The reaction time for the above reaction is varied depending upon the reaction temperature, the kind and amount of the catalyst and the like, and when, for example, HMDI is used as the starting material and 3-methyl-1-phenyl-2-phosphorene-1-oxide is added in a proportion of 1% by weight based on the total weight of the isocyanates and the reaction is effected at a reaction temperature of 180° C., it is possible to obtain in about 20 hours a carbodiimide compound resulting from HMDI, and even when IPDI is used as the starting material the same applies.

When, for example, a mixture of TMXDI and HMDI is used as the starting material, it is possible to obtain a carbodiimide compound resulting from the mixture of TMXDI and HMDI similarly to the above.

Incidentally, the proceeding of the reaction may be confirmed by observing the absorption of isocyanate group at 2258 cm⁻¹ in an infrared absorption spectrum or confirmed by a titration method.

In the above reaction, when (1) HMDI, IPDI or a mixture of HMDI and IPDI, or (2) a mixture of TMXDI with HMDI, IPDI or a mixture of HMDI and IPDI is used, a carbodiimide represented by the following formula (IV) can be obtained:

    OCN--(R.sub.1 --NCN).sub.n --R.sub.2 --NCO                 (IV)

wherein R₁ and R₂ may be the same as or different from each other and each represents the residue of TMXDI, HMDI or IPDI freed from NCO group; and the polymerization style of the above isocyanates may be a random polymerization or a block polymerization; and n is an integer of 2 or more.

As the carbodiimide which is the main component of the present hydrolysis stabilizer for an ester group-containing resin, there may be a product obtained by end-blocking a carbodiimide having terminal isocyanate groups obtained by the above-mentioned method, with an amine, a carboxylic acid, an acid anhydride, a monoisocyanate or the like.

When the terminal isocyanate of the carbodiimide is blocked with a monoisocyanate, a carbodiimide represented by the following formula (V) can be obtained:

    R.sub.3 --NCN--(R.sub.5 --NCN).sub.m --R.sub.4             (V)

wherein R₃ and R₄ may be the same as or different from each other and each represents the residue of the monoisocyanate freed from NCO group; m is an integer of 1 or more; and R₅ represents the residue of the diisocyanate used in the reaction similarly to R₁ and R₂.

Incidentally, the proportion (mole ratio) of the diisocyanate [(1) HMDI, IPDI or a mixture of HMDI and IPDI or (2) a mixture of TMXDI with HMDI, IPDI or a mixture of HMDI and IPDI] to the monoisocyanate is 1:2-30:2 , preferably 4:2-19:2, and when the diisocyanate and the monoisocyanate are used in a proportion of 3:2, the number of carbodiimide units in one molecule, namely n, becomes 4 and when the proportion is 19:2, n becomes 20.

When the terminals of the carbodiimide are blocked with the monoisocyanate, it is favorable, for obtaining a carbodiimide having the desired molecular weight, that the diisocyanate and the monoisocyanate are previously mixed to effect carbodiimidization, because it is possible to control the amount of the monocarbodiimide produced by condensation of the monoisocyanate molecules with each other.

The monoisocyanate used for blocking the terminals of the carbodiimide includes n-butyl isocyanate, tert-butyl isocyanate, isobutyl isocyanate, ethyl isocyanate, n-propyl isocyanate, cyclohexyl isocyanate, n-octyl isocyanate and the like, and these may be used alone or in admixture of two or more.

Moreover, when the terminals of a carbodiimide are blocked with a monofunctional compound having a group capable of reacting with the isocyanate group, for example, an amine, a carboxylic acid or an acid anhydride, a carbodiimide represented by the formula (VI) can be obtained:

    R.sub.6 --X--(R.sub.1 --NCN).sub.p --R.sub.2 --X--R.sub.7  (VI)

wherein R₆ and R₇ may be the same as or different from each other and each represents the residue of the monofunctional compound having a group capable of reacting with an isocyanate group, for example, an amine, a carboxylic acid or an acid anhydride, formed by reaction with the isocyanate; X represents a bond formed by the reaction of the monofunctional compound having a group capable of reacting with the isocyanate group with the isocyanate; and p is an integer of 2 or more.

When the terminals of a carbodiimide are blocked with a monofunctional compound having a group capable of reacting with an isocyanate group, for example, an amine, a carboxylic acid or an acid anhydride, the reaction between the isocyanate and the end-blocking agent may be effected before the carbodiimidization or may be effected after the carbodiimidization to a suitable degree of polymerization by adding the end-blocking agent in an amount equivalent to the residual isocyanate.

The present hydrolysis stabilizer for an ester group-containing resin comprises the above-mentioned carbodiimide as a main component, and in the actual use, the above carbodiimide may be used as a single component or may be used in combination with an appropriate adjuvant.

The present process for the hydrolysis stabilization of an ester group-containing resin comprises mixing the above-mentioned carbodiimide with the ester type resin. The mixing method is not critical and any appropriate mixing method can be adopted.

The proportion of the above carbodiimide to the ester group-containing resin is 0.01 to 5% by weight, preferably 0.3 to 1% by weight, and when the proportion is less than 0.01% by weight, the amount of the carbodiimide bond for the ester group becomes small, the hydrolysis stabilization effect cannot be said to be sufficient. When the proportion exceeds 5% by weight, the carbodiimide exhibits its plasticizing effect on the ester group-containing resin and adversely affects the physical properties of the resin.

Incidentally, as carbodiimides having particularly preferable hydrolysis resistance, there can be mentioned carbodiimides having a degree of polymerization of 5 to 30 obtained from HMDI and a monoisocyanate, for example, cyclohexyl isocyanate; end-blocked carbodiimides having a degree of polymerization of 5 to 30 obtained from HMDI and an amine, for example, cyclohexylamine; carbodiimides having a degree of polymerization of 5 to 30 derived from a mixture of HMDI:TMXDI=10:1-1:10 and end-blocked with a monoisocyanate such as cyclohexyl isocyanate or the like or an amine such as cyclohexylamine or the like; etc.

JP-A-07-017939 discloses isocyanate-terminated carbodiimides having a degree of polymerization (n) of 0 to 10 and an improved compatibility. However, this isocyanate is low in reactivity owing to steric hindrance and when the carbodiimide is mixed with the ester group-containing resin, the reaction of the isocyanate with the carboxyl or hydroxyl group present at the ends of the ester group-containing resin is slow and the isocyanate remains as such in the ester group-containing resin even after the melt-kneading. Therefore, there is such a problem that this isocyanate reacts with moisture to generate carbon dioxide, whereby voids and the like are formed in the ester group-containing resin.

On the other hand, in the case of the present hydrolysis stabilizer for an ester group-containing resin, the reactivity of the terminal isocyanate group of the carbodiimide resulting from HMDI, IPDI or a mixture of HMDI and IPDI which is the main component of the hydrolysis stabilizer, is sufficiently high even when the carbodiimide results from a mixture of TMXDI with HMDI, IPDI or a mixture of HMDI and IPDI. When the carbodiimide is melt-kneaded with the ester group-containing resin, the terminal isocyanate groups are consumed by the reaction with the carboxyl or hydroxyl group present at the ends of the ester group-containing resin, and there is substantially no case where the isocyanate remains as such in the ester group-containing resin after the melt-kneading. Therefore, there is go problem of voids and the like due to carbon dioxide.

Furthermore, JP-A-07-017939 discloses carbodiimides in which the terminal isocyanates are blocked with an alcohol or an amine. However, as described above, this carbodiimide is low in reactivity because of steric hindrance, and in order to obtain the desired hydrolysis stabilizing effect, it is necessary that the carbodiimide be added in an amount as large as possible within the limited addition amount range (when the amount of the carbodiimide added is too large, there appears a plasticizing effect on the ester group-containing resin). Accordingly, the blocking of the terminal isocyanate group with an alcohol or an amine results in an increase of molecular weight and also a decrease of the above-mentioned addition amount, and hence, is not desirable in view of the hydrolysis stabilizing effect.

On the other hand, in the case of the present hydrolysis stabilizer for an ester group-containing resin, the reactivity of the terminal isocyanate group of the carbodiimide which is the main component of the stabilizer, is sufficiently high as described above, and hence, even when the terminal isocyanate group is blocked with an alcohol or an amine to increase the molecular weight, a sufficient hydrolysis stabilizing effect is exhibited without increasing the addition amount so much.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Examples are shown below to explain the present invention in more detail.

Synthesis of Carbodiimides Synthesis Example 1

To 300 g of HMDI was added, as a carbodiimidization catalyst, 1.5 g of 3-methyl-1-phenyl-2-phosphorene-1-oxide (referred to hereinafter as carbodiimidization catalyst), and they were subjected to a condensation reaction at 180° C. for 10 hours in a nitrogen atmosphere to obtain a carbodiimide resulting from HMDI (degree of polymerization=3).

Synthesis Examples 2 to 4

The same procedure as in Synthesis Example 1 was repeated, except that the reaction time was changed as shown in Table 1 to obtain carbodiimides as shown in Table 1.

                  TABLE 1                                                          ______________________________________                                                        Reaction time                                                                             Polymerization                                       Synthesis Example                                                                             (hr)       degree                                               ______________________________________                                         2              15         10                                                   3              27         20                                                   4              35         30                                                   ______________________________________                                    

Synthesis Example 5

To 300 g of HMDI was added 1.5 g of the carbodiumidization catalyst and they were subjected to a reaction at 185° C. for 5 hours while nitrogen was bubbled thereinto, to obtain a carbodiimide resulting from HMDI (degree of polymerization=10).

Synthesis Examples 6 to 8

The same procedure as in Synthesis Example 1 was repeated, except that the reaction time was changed as shown in Table 2 to obtain carbodiimides shown in Table 2.

                  TABLE 2                                                          ______________________________________                                                        Reaction time                                                                             Polymerization                                       Synthesis Example                                                                             (hr)       degree                                               ______________________________________                                         6              16         10                                                   7              28         20                                                   8              38         30                                                   ______________________________________                                    

Synthesis Example 9

To a mixture of 236 g of HMDI with 25.0 g of cyclohexyl isocyanate (referred to hereinafter as CHI) was added 2.60 g of the carbodiimidization catalyst, and they were subjected to a reaction at 185° C. for 19 hours while nitrogen was bubbled thereinto, to obtain a carbodiimide resulting from HMDI and CHI (degree of polymerization=10).

Synthesis Examples 10 to 14

The starting materials and the reaction conditions were changed as shown in Table 3 to obtain carbodiimides shown in Table 3 in which CHI means a cyclohexyl isocyanate.

                  TABLE 3                                                          ______________________________________                                         Synthesis Example                                                                          10      11       12    13    14                                    ______________________________________                                         Diisocyanate                                                                               HMDI    HMDI     IPDI  IPDI  IPDI                                  Amount (g)  498     760      200   400   622                                   Monoisocyanate                                                                             CHI     CHI      CHI   CHI   CHI                                   Amount (g)  25      25       25    25    25                                    Catalyst amount (g)                                                                        5.2     7.8      2.3   4.3   6.2                                   Reaction time (hr)                                                                         20      48       21    27    52                                    Polymerization degree                                                                      20      30       10    20    30                                    ______________________________________                                    

Synthesis Example 15

To 288 g of HMDI was added 20 g of cyclohexylamine and they were stirred at 100° C. for one hour while nitrogen was bubbled thereinto and subsequently 2.9 g of the carbodiimidization catalyst was added thereto, after which the resulting mixture was subjected to a reaction at 185° C. for 30 hours, to obtain a carbodiimide resulting from HMDI and having terminal urea bonds (degree of polymerization=10).

Synthesis Examples 16 to 30

The end-blocking agent was changed to an alcohol, an amine, a carboxylic acid or an acid anhydride as shown in Tables 4, 5 and 6, and in the same manner as in Synthesis Example 13, there were obtained carbodiimides having a urea bond, a urethane bond, an imido bond or an amido bond in the molecular chain as shown in Tables 4, 5 and 6.

                  TABLE 4                                                          ______________________________________                                         Synthesis Example                                                                         16      17      18    19      20                                    ______________________________________                                         Diisocyanate                                                                              HMDI    IPDI    IPDI  HMDI    HMDI                                  Amount (g) 498     245     467   288     498                                   Blocking agent                                                                            Cyclo-  IPDI    IPDI  Cyclohexyl-                                                                            HMDI                                             hexyl-  245     467   carboxylic                                                                             498                                              amine                 acid                                          Amount (g) 20      20      20    26      26                                    Catalyst amount (g)                                                                       5.5     2.5     4.7   2.9     5.5                                   Reaction time (hr)                                                                        52      30      50    32      48                                    Polymerization                                                                            20      10      20    10      20                                    degree                                                                         ______________________________________                                    

                  TABLE 5                                                          ______________________________________                                         Synthesis Example                                                                          21      22      23     24    25                                    ______________________________________                                         Diisocyanate                                                                               HMDI    HMDI    HMDI   HMDI  HMDI                                  Amount (g)  288     498     288    498   288                                   Blocking agent                                                                             Phthalic                                                                               HMDI    Ben-   HMDI  Dibutyl-                              Amount (g)  anhy-   498     zoic   498   amine                                             dride   30      acid   24                                                      30              24           26                                    Catalyst amount (g)                                                                        2.9     5.5     2.9    5.5   2.9                                   Reaction time (hr)                                                                         35      52      31     50    32                                    Polymerization degree                                                                      10      20      10     20    10                                    ______________________________________                                    

                  TABLE 6                                                          ______________________________________                                         Synthesis Example                                                                          26      27       28    29    30                                    ______________________________________                                         Diisocyanate                                                                               HMDI    IPDI     IPDI  IPDI  IPDI                                  Amount (g)  498     245      467   245   467                                   Blocking agent                                                                             Di-     Cyclohe- IPDI  Phthalic                                                                             IPDI                                  Amount (g)  butyl-  xyl-     467   anhy- 467                                               amine   carboxy- 26    dride 30                                                        lic acid                                                               26      26             30                                          Catalyst amount (g)                                                                        5.5     2.5      4.7   2.5   4.7                                   Reaction time (hr)                                                                         48      30       50    30    50                                    Polymerization degree                                                                      20      10       20    10    20                                    ______________________________________                                    

EXAMPLE 1

A polybutylene terephthalate [PBT] manufactured by DAINIPPON INK & CHEMICALS INC. (Product No. BT-1000) was melt-kneaded with 1% by weight of the present hydrolysis stabilizer for an ester group-containing resin which comprised as the main component one of the carbodiimides obtained in Synthesis Examples 1 to 30, by means of a twin screw extruder and injection molded into JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength of the sample was measured by a tensile tester every time shown in Table 7. The results are shown in Tables 7 to 9 [incidentally, in Tables 7 to 9, the numerals in the uppermost section refer to Synthesis Example Nos. in which the carbodiimide was synthesized, and the term "blank" means a sample in which no present hydrolysis stabilizer for an ester group-containing resin was the same applies hereinafter)].

                                      TABLE 7                                      __________________________________________________________________________     t/day                                                                              blank                                                                             1   2  3   4  5   6  7   8  9                                           __________________________________________________________________________     0   610                                                                               610 610                                                                               610 620                                                                               610 610                                                                               610 610                                                                               610                                         10  410                                                                               520 540                                                                               540 540                                                                               520 530                                                                               530 540                                                                               570                                         15  250                                                                               400 420                                                                               430 430                                                                               400 420                                                                               420 420                                                                               460                                         20  150                                                                               200 230                                                                               230 230                                                                               190 220                                                                               230 230                                                                               260                                         30  100                                                                               150 170                                                                               170 170                                                                               140 170                                                                               170 170                                                                               190                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 8                                      __________________________________________________________________________     t/day                                                                              10 11  12 13  14 15  16 17  18 19                                          __________________________________________________________________________     0   610                                                                               620 610                                                                               610 610                                                                               610 619                                                                               610 610                                                                               610                                         10  580                                                                               590 560                                                                               570 570                                                                               580 580                                                                               560 560                                                                               560                                         15  470                                                                               480 450                                                                               460 460                                                                               470 470                                                                               450 450                                                                               450                                         20  260                                                                               270 250                                                                               260 260                                                                               260 270                                                                               250 250                                                                               240                                         30  200                                                                               200 190                                                                               190 200                                                                               200 200                                                                               180 190                                                                               170                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 9                                      __________________________________________________________________________     t/day                                                                              20 21 22 23 24 25  26 27 28 29 30                                          __________________________________________________________________________     0   610                                                                               610                                                                               610                                                                               610                                                                               610                                                                               600 600                                                                               610                                                                               600                                                                               610                                                                               610                                         10  560                                                                               560                                                                               570                                                                               560                                                                               560                                                                               570 570                                                                               550                                                                               560                                                                               560                                                                               560                                         15  450                                                                               450                                                                               450                                                                               450                                                                               450                                                                               460 460                                                                               440                                                                               450                                                                               440                                                                               450                                         20  250                                                                               250                                                                               250                                                                               240                                                                               250                                                                               260 270                                                                               240                                                                               240                                                                               240                                                                               250                                         30  180                                                                               180                                                                               180                                                                               170                                                                               180                                                                               190 200                                                                               170                                                                               170                                                                               170                                                                               170                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

EXAMPLE 2

To a urethane elastomer manufactured by Nisshinbo Industries, Inc. (Reference No. F-30) was added 1% by weight of the present hydrolysis stabilizer for an ester group-containing resin comprising as the main component one of the carbodiimides obtained in Synthesis Examples 1 to 30, and the resulting mixture was molded into a film by a cast method, after which the film was punched to JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength of the sample was measured by a tensile tester every time shown in Tables 10 to 12. The results are shown in Tables 10 to 12.

                                      TABLE 10                                     __________________________________________________________________________     t/day                                                                              blank                                                                             1   2  3   4  5   6  7   8  9                                           __________________________________________________________________________     0   870                                                                               880 880                                                                               890 890                                                                               870 880                                                                               880 880                                                                               870                                         3   520                                                                               650 660                                                                               660 660                                                                               640 650                                                                               650 660                                                                               710                                         7   140                                                                               570 580                                                                               590 590                                                                               560 570                                                                               570 570                                                                               590                                         10  -- 510 520                                                                               530 530                                                                               500 510                                                                               500 510                                                                               530                                         15  -- 190 200                                                                               200 200                                                                               110 110                                                                               200 210                                                                               210                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 11                                     __________________________________________________________________________     t/day                                                                              10 11 12 13 14 15  16 17 18 19 20                                          __________________________________________________________________________     0   880                                                                               880                                                                               880                                                                               880                                                                               880                                                                               870 870                                                                               870                                                                               870                                                                               870                                                                               870                                         3   710                                                                               720                                                                               710                                                                               710                                                                               710                                                                               710 710                                                                               700                                                                               700                                                                               710                                                                               710                                         7   600                                                                               600                                                                               590                                                                               590                                                                               600                                                                               350 350                                                                               320                                                                               350                                                                               580                                                                               580                                         10  530                                                                               530                                                                               520                                                                               540                                                                               540                                                                               320 340                                                                               300                                                                               310                                                                               500                                                                               500                                         15  240                                                                               250                                                                               200                                                                               190                                                                               200                                                                               110 130                                                                               100                                                                               120                                                                               190                                                                               200                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 12                                     __________________________________________________________________________     t/day                                                                              21 22  23 24  25 26  27 28  29 30                                          __________________________________________________________________________     0   870                                                                               870 870                                                                               870 880                                                                               880 870                                                                               870 870                                                                               870                                         3   700                                                                               710 710                                                                               710 710                                                                               720 670                                                                               670 670                                                                               640                                         7   560                                                                               570 570                                                                               570 570                                                                               580 530                                                                               550 540                                                                               550                                         10  500                                                                               510 500                                                                               510 510                                                                               510 470                                                                               480 510                                                                               510                                         15  180                                                                               190 170                                                                               180 170                                                                               180 140                                                                               170 170                                                                               180                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________      --: destructed                                                           

EXAMPLE 3

A polybutylene terephthalate [PBT] elastomer manufactured by DAINIPPON INK & CHEMICALS, INC. (Product No. GRILUX [registered trademark] EH-700) and 0.5% by weight of the present hydrolysis stabilizer for an ester group-containing resin comprising as the main component one of the carbodiimides obtained in Synthesis Examples 1 to 30 were melt-mixed and extruded using a twin screw extruder and then formed into a film of about 500 μm using a T-die, after which the film thus obtained was injection molded into JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength was measured by a tensile tester every time shown in Tables 13 to 15. The results are shown in Tables 13 to 15.

                                      TABLE 13                                     __________________________________________________________________________     t/day                                                                              blank                                                                             1  2  3  4  5   6  7  8  9  10                                          __________________________________________________________________________     0   350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               350                                                                               350                                                                               350                                         10  330                                                                               350                                                                               350                                                                               350                                                                               350                                                                               340 340                                                                               340                                                                               350                                                                               350                                                                               350                                         15  310                                                                               340                                                                               350                                                                               350                                                                               350                                                                               330 340                                                                               340                                                                               340                                                                               350                                                                               350                                         20  290                                                                               320                                                                               330                                                                               340                                                                               340                                                                               320 330                                                                               340                                                                               340                                                                               350                                                                               350                                         30  220                                                                               320                                                                               330                                                                               330                                                                               340                                                                               310 320                                                                               330                                                                               330                                                                               340                                                                               340                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 14                                     __________________________________________________________________________     t/day                                                                              11 12 13 14 15 16  17 18 19 20 21                                          __________________________________________________________________________     0   350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               350                                                                               350                                                                               350                                         10  350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               340                                                                               340                                                                               340                                         15  350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               340                                                                               340                                                                               340                                                                               340                                         20  350                                                                               340                                                                               340                                                                               340                                                                               350                                                                               350 340                                                                               340                                                                               330                                                                               330                                                                               320                                         30  340                                                                               330                                                                               340                                                                               340                                                                               340                                                                               340 330                                                                               330                                                                               320                                                                               320                                                                               310                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                  TABLE 15                                                         ______________________________________                                         t/day 22     23     24   25   26   27   28   29   30                           ______________________________________                                         0     350    350    350  350  350  350  350  350  350                          10    340    340    340  350  350  340  340  340  340                          15    340    330    330  340  340  330  330  320  330                          20    320    310    320  330  340  320  320  310  310                          30    310    300    310  320  320  300  300  300  300                          (Kg/cm.sup.2)                                                                  ______________________________________                                    

EXAMPLE 4

A polyethylene terephthalate [PET] resin manufactured by KANEBO LTD. (Product No. EFG-7) and 0.5% by weight of the present hydrolysis stabilizer for an ester group-containing resin comprising as the main component one of the carbodiimides obtained in Synthesis Examples 1 to 30 were melt-mixed and extruded using a twin screw extruder and then formed into a film of about 500 μm using a T-die, after which the film thus obtained was injection molded into JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength was measured by a tensile tester every time shown in Tables 16 to 18. The results are shown in Tables 16 to

                                      TABLE 16                                     __________________________________________________________________________     t/day                                                                              blank                                                                             1  2  3  4  5   6  7  8  9  10                                          __________________________________________________________________________     0   630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630 630                                                                               630                                                                               630                                                                               630                                                                               630                                         10  640                                                                               650                                                                               650                                                                               640                                                                               650                                                                               650 650                                                                               650                                                                               650                                                                               650                                                                               640                                         30  590                                                                               650                                                                               650                                                                               650                                                                               650                                                                               650 650                                                                               650                                                                               650                                                                               650                                                                               650                                         60  460                                                                               630                                                                               640                                                                               640                                                                               640                                                                               620 630                                                                               640                                                                               640                                                                               650                                                                               650                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 17                                     __________________________________________________________________________     t/day                                                                              11 12 13 14 15 16  17 18 19 20 21                                          __________________________________________________________________________     0   630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630 630                                                                               630                                                                               630                                                                               630                                                                               630                                         10  650                                                                               640                                                                               650                                                                               650                                                                               650                                                                               650 650                                                                               650                                                                               650                                                                               650                                                                               650                                         30  650                                                                               650                                                                               650                                                                               650                                                                               650                                                                               650 650                                                                               650                                                                               650                                                                               650                                                                               650                                         60  650                                                                               620                                                                               630                                                                               630                                                                               640                                                                               650 620                                                                               620                                                                               600                                                                               600                                                                               600                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                  TABLE 18                                                         ______________________________________                                         t/day 22     23     24   25   26   27   28   29   30                           ______________________________________                                         0     630    630    630  630  630  630  630  630  630                          10    650    650    650  650  650  650  650  650  650                          30    650    650    650  650  650  650  650  650  650                          60    620    600    600  640  640  600  600  600  600                          (Kg/cm.sup.2)                                                                  ______________________________________                                    

Synthesis of Carbodiimides Synthesis Examples 31 to 39

To one of the diisocyanate mixtures shown in Tables 19 and 20 was added 1.5% by weight, based on the total weight of the isocyanates, of the carbodiimidization catalyst and the resulting mixture was heated at 185° C. to be subjected to a reaction until the degree of polymerization (n) became 10.

                                      TABLE 19                                     __________________________________________________________________________     Synthesis Example                                                                         31  32   33   34   35  36                                           __________________________________________________________________________     Diisocyanate                                                                              HMDI                                                                               HMDI HMDI IPDI IPDI                                                                               IPDI                                         Amount (g) 65.5                                                                               131.0                                                                               196.5                                                                               55.6 111.1                                                                              166.7                                                   TMXDI                                                                              TMXDI                                                                               TMXDI                                                                               TMXDI                                                                               TMXDI                                                                              TMXDI                                                   183.0                                                                              122.0                                                                               61.0 183.0                                                                               122.0                                                                              61.0                                         Monoisocyanate                                                                            Not Not  Not  Not  Not Not                                                     used                                                                               used used used used                                                                               used                                         Catalyst amount (g)                                                                       3.7 3.8  3.9  3.6  3.5 3.4                                          Reaction time (hr)                                                                        30  25   20   30   26  20                                           Polymerization degree                                                                     10  10   10   10   10  10                                           __________________________________________________________________________

                  TABLE 20                                                         ______________________________________                                         Synthesis Example                                                                              37        38       39                                          ______________________________________                                         Diisocyanate    HMDI      HMDI     HMDI                                        Amount (g)      65.5      131.0    196.5                                                       IPDI      IPDI     IPDI                                                        166.7     111.1    55.6                                        Monoisocyanate  Not       Not      Not                                                         used      used     used                                        Catalyst amount (g)                                                                            3.5       3.6      3.8                                         Reaction time (hr)                                                                             20        19       19                                          Polymerization degree                                                                          10        10       10                                          ______________________________________                                    

Synthesis Examples 40 to 48

To one of the mixtures shown in Tables 21 and 22 was added cyclohexyl isocyanate so that the degree of polymerization (n) becomes 10 (diisocyanate:monoisocyanate=9:2 by mole), and the carbodiimidization catalyst was added in a proportion of 1.5% by weight based on the total weight of the isocyanates, after which the resulting mixture was heated at 185° C. to be subjected to a reaction until the peak of the isocyanate disappeared in the infrared absorption (IR) spectrum.

                  TABLE 21                                                         ______________________________________                                         Synthesis Example                                                                              40        41       42                                          ______________________________________                                         Diisocyanate    HMDI      HMDI     HMDI                                        Amount (g)      65.5      131.0    196.5                                                       TMXDI     TMXDI    TMXDI                                                       183.0     122.0    61.0                                        Monoisocyanate  Cyclo-    Cyclo-   Cyclo-                                      Amount (g)      hexyl     hexyl    hexyl                                                       isocya-   isocya-  isocya-                                                     nate      nate     nate                                                        27.8      27.8     27.8                                        Catalyst amount (g)                                                                            4.1       4.2      4.3                                         Reaction time (hr)                                                                             28        24       19                                          Polymerization degree                                                                          10        10       10                                          ______________________________________                                    

                                      TABLE 22                                     __________________________________________________________________________     Synthesis Example                                                                         43  44   45   46   47  48                                           __________________________________________________________________________     Diisocyanate                                                                              IPDI                                                                               IPDI IPDI HMDI HMDI                                                                               HMDI                                         Amount (g) 55.6                                                                               111.1                                                                               166.7                                                                               65.5 131.0                                                                              196.5                                                   TMXDI                                                                              TMXDI                                                                               TMXDI                                                                               IPDI IPDI                                                                               IPDI                                                    183.0                                                                              122.0                                                                               61.0 166.7                                                                               111.1                                                                              55.6                                         Monoisocyanate                                                                            Cyclo-                                                                             Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                             Cyclo-                                       Amount (g) hexyl                                                                              hexyl                                                                               hexyl                                                                               hexyl                                                                               hexyl                                                                              hexyl                                                   isocy-                                                                             isocy-                                                                              isocy-                                                                              isocy-                                                                              isocy-                                                                             isocy-                                                  anate                                                                              anate                                                                               anate                                                                               anate                                                                               anate                                                                              anate                                                   27.8                                                                               27.8 27.8 27.8 27.8                                                                               27.8                                         Catalyst amount (g)                                                                       4.0 3.9  3.8  3.5  3.6 3.8                                          Reaction time (hr)                                                                        30  25   20   21   20  20                                           Polymerization degree                                                                     10  10   10   10   10  10                                           __________________________________________________________________________

Synthesis Examples 49 to 57

To one of the mixtures shown in Tables 23 and 24 was added cyclohexylamine so that the degree of polymerization (n) became 10 (diisocyanate:amine=11:2 by mole), and the carbodiimidization catalyst was added in a proportion of 1.5% by weight based on the total weight of the isocyanates, after which the resulting mixture was heated at 185° C. to be subjected to a reaction until the peak of the isocyanate disappeared in IR.

                                      TABLE 23                                     __________________________________________________________________________     Synthesis Example                                                                         49  50   51   52   53  54                                           __________________________________________________________________________     Diisocyanate                                                                              HMDI                                                                               HMDI HMDI IPDI IPDI                                                                               IPDI                                         Amount (g) 65.5                                                                               131.0                                                                               196.5                                                                               55.6 111.1                                                                              166.7                                                   TMXDI                                                                              TMXDI                                                                               TMXDI                                                                               TMXDI                                                                               TMXDI                                                                              TMXDI                                                   183.0                                                                              122.0                                                                               61.0 183.0                                                                               122.0                                                                              61.0                                         Amine      Cyclo-                                                                             Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                             Cyclo-                                       Amount (g) hexyl                                                                              hexyl                                                                               hexyl                                                                               hexyl                                                                               hexyl                                                                              hexyl                                                   amine                                                                              amine                                                                               amine                                                                               amine                                                                               amine                                                                              amine                                                   22.0                                                                               22.0 22.0 22.0 22.0                                                                               22.0                                         Catalyst amount (g)                                                                       3.7 3.8  3.9  3.6  3.5 3.4                                          Reaction time (hr)                                                                        29  25   19   30   25  20                                           Polymerization degree                                                                     9   9    9    9    9   9                                            __________________________________________________________________________

                  TABLE 24                                                         ______________________________________                                         Synthesis Example                                                                              55        56       57                                          ______________________________________                                         Diisocyanate    HMDI      HMDI     HMDI                                        Amount (g)      65.5      131.3    196.5                                                       IPDI      IPDI     IPDI                                                        166.7     111.1    55.6                                        Amine           Cyclo-    Cyclo-   Cyclo-                                      Amount (g)      hexyl     hexyl    hexyl                                                       amine     amine    amine                                                       22.0      22.0     22.0                                        Catalyst amount (g)                                                                            3.5       3.6      3.8                                         Reaction time (hr)                                                                             19        22       20                                          Polymerization degree                                                                          9         9        9                                           ______________________________________                                    

Synthesis Examples 58 to 66

To one of the mixtures shown in Tables 25 and 26 was added cyclohexyl isocyanate so that the degree of polymerization (n) became 20 (duisocyanate:monoisocyanate=19:2 by mole) and the carbodiimidization catalyst was added in a proportion of 1.5% by weight based on the total weight of the isocyanates, after which the resulting mixture was heated at 185° C. to be subjected to a reaction until the peak of the isocyanate disappeared in IR.

                  TABLE 25                                                         ______________________________________                                         Synthesis Example                                                                              58        59       60                                          ______________________________________                                         Diisocyanate    HMDI      HMDI     HMDI                                        Amount (g)      65.5      131.0    196.5                                                       TMXDI     TMXDI    TMXDI                                                       183.0     122.0    61.0                                        Monoisocyanate  Cyclo-    Cyclo-   Cyclo-                                                      hexyl     hexyl    hexyl                                       Amount (g)      isocy-    isocy-   isocy-                                                      anate     anate    anate                                                       13.2      13.2     13.2                                        Catalyst amount (g)                                                                            3.9       4.0      4.1                                         Reaction time (hr)                                                                             30        24       21                                          Polymerization degree                                                                          20        20       20                                          ______________________________________                                    

                                      TABLE 26                                     __________________________________________________________________________     Synthesis Example                                                                         61  62   63   64   65  66                                           __________________________________________________________________________     Diisocyanate                                                                              IPDI                                                                               IPDI IPDI HMDI HMDI                                                                               HMDI                                         Amount (g) 55.6                                                                               111.1                                                                               166.7                                                                               65.5 131.0                                                                              196.5                                                   TMXDI                                                                              TMXDI                                                                               TMXDI                                                                               IPDI IPDI                                                                               IPDI                                                    183.0                                                                              122.0                                                                               61.0 166.7                                                                               111.1                                                                              55.6                                         Monoisocyanate                                                                            Cyclo-                                                                             Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                             Cyclo-                                       Amount (g) hexyl                                                                              hexyl                                                                               hexyl                                                                               hexyl                                                                               hexyl                                                                              hexyl                                                   isocy-                                                                             isocy-                                                                              isocy-                                                                              isocy-                                                                              isocy-                                                                             isocy-                                                  anate                                                                              anate                                                                               anate                                                                               anate                                                                               anate                                                                              anate                                                   13.2                                                                               13.2 13.2 13.2 13.2                                                                               13.2                                         Catalyst amount (g)                                                                       3.8 3.7  3.6  3.7  3.8 4.0                                          Reaction time (hr)                                                                        29  24   20   23   19  20                                           Polymerization degree                                                                     20  20   20   20   20  20                                           __________________________________________________________________________

Synthesis Examples 67 to 75

To one of the mixtures shown in Tables 27 and 28 was added cyclohexylamine so that the degree of polymerization (n) became 20 (diisocyanate:amine=21:2 by mole), and the carbodiimidization catalyst was added in a proportion of 1.5% by weight based on-the total weight of the isocyanates, after which the resulting mixture was heated at 185° C. to be subjected to a reaction until the peak of the isocyanate disappeared in IR.

                                      TABLE 27                                     __________________________________________________________________________     Synthesis Example                                                                         67  68   69   70   71  72                                           __________________________________________________________________________     Diisocyanate                                                                              HMDI                                                                               HMDI HMDI IPDI IPDI                                                                               IPDI                                         Amount (g) 65.5                                                                               131.0                                                                               196.5                                                                               55.6 111.1                                                                              166.7                                                   TMXDI                                                                              TMXDI                                                                               TMXDI                                                                               TMXDI                                                                               TMXDI                                                                              TMXDI                                                   183.0                                                                              122.0                                                                               61.0 183.0                                                                               122.0                                                                              61.0                                         Amine      Cyclo-                                                                             Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                             Cyclo-                                       Amount (g) hexyl                                                                              hexyl                                                                               hexyl                                                                               hexyl                                                                               hexyl                                                                              hexyl                                                   amine                                                                              amine                                                                               amine                                                                               amine                                                                               amine                                                                              amine                                                   10.4                                                                               10.4 10.4 10.4 10.4                                                                               10.4                                         Catalyst amount (g)                                                                       3.7 3.8  3.9  3.6  3.5 3.4                                          Reaction time (hr)                                                                        52  50   48   51   50  50                                           Polymerization degree                                                                     19  19   19   19   19  19                                           __________________________________________________________________________

                  TABLE 28                                                         ______________________________________                                         Synthesis Example                                                                              73        74       75                                          Diisocyanate    HMDI      HMDI     HMDI                                        Amount (g)      65.5      131.0    196.5                                                       IPDI      IPDI     IPDI                                                        166.7     111.1    55.6                                        Amine           Cyclo-    Cyclo-   Cyclo-                                      Amount (g)      hexyl     hexyl    hexyl                                                       amine     amine    amine                                                       10.4      10.4     10.4                                        Catalyst amount (g)                                                                            3.5       3.6      3.8                                         Reaction time (hr)                                                                             47        48       48                                          Polymerization degree                                                                          19        19       19                                          ______________________________________                                    

Synthesis Examples 76 to 84

To one of the mixtures shown in Tables 29 and 30 was added cyclohexylcarboxylic acid so that the degree of polymerization (n) became 9 (diisocyanate:cyclohexylcarboxylic acid=10:2 by mole), and the carbodiimidization catalyst was added in a proportion of 1.5% by weight based on the total weight of the isocyanates, after which the resulting mixture was heated at 185° C. to be subjected to a reaction until the peak of the isocyanate disappeared in IR.

                  TABLE 29                                                         ______________________________________                                         Synthesis Example                                                                              76        77       78                                          ______________________________________                                         Diisocyanate    HMDI      HMDI     HMDI                                        Amount (g)      65.5      131.0    196.5                                                       TMXDI     TMXDI    TMXDI                                                       183.0     122.0    61.0                                        Carboxylic acid Cyclo-    Cyclo-   Cyclo-                                      Amount (g)      hexyl     hexyl    hexyl                                                       car-      car-     car-                                                        boxyli    boxyli   boxyli                                                      c acid    c acid   c acid                                                      28.5      28.5     28.5                                        Catalyst amount (g)                                                                            3.7       3.8      3.9                                         Reaction time (hr)                                                                             30        25       20                                          Polymerization degree                                                                          9         9        9                                           ______________________________________                                    

                                      TABLE 30                                     __________________________________________________________________________     Synthesis Example                                                                         79  80   81   82   83  84                                           __________________________________________________________________________     Diisocyanate                                                                              IPDI                                                                               IPDI IPDI HMDI HMDI                                                                               HMDI                                         Amount (g) 55.6                                                                               111.1                                                                               166.7                                                                               65.5 131.0                                                                              196.5                                                   TMXDI                                                                              TMXDI                                                                               TMXDI                                                                               IPDI IPDI                                                                               IPDI                                                    183.0                                                                              122.0                                                                               61.0 166.7                                                                               111.1                                                                              55.6                                         Carboxylic acid                                                                           Cyclo-                                                                             Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                              Cyclo-                                                                             Cyclo-                                       Amount (g) hexyl                                                                              hexyl                                                                               hexyl                                                                               hexyl                                                                               hexyl                                                                              hexyl                                                   car-                                                                               car- car- car- car-                                                                               car-                                                    boxylic                                                                            boxylic                                                                             boxylic                                                                             boxylic                                                                             boxylic                                                                            boxylic                                                 acid                                                                               acid acid acid acid                                                                               acid                                                    28.5                                                                               28.5 28.5 28.5 28.5                                                                               28.5                                         Catalyst amount (g)                                                                       3.6 3.5  3.4  3.5  3.6 3.8                                          Reaction time (hr)                                                                        30  26   20   20   19  19                                           Polymerization degree                                                                     9   9    9    9    9   9                                            __________________________________________________________________________

Synthesis Examples 85 to 92

To one of the mixtures shown in Tables 31 and 32 was added phthalic anhydride so that the degree of polymerization (n) became 9 (diisocyanate:phthalic anhydride=10:2 by mole), and the carbodiimidization catalyst was added in a proportion of 1.5% by weight based on the total weight of the isocyanates, after which the resulting mixture was heated at 185° C. to be subjected to a reaction until the peak of the isocyanate disappeared in IR.

                                      TABLE 31                                     __________________________________________________________________________     Synthesis Example                                                                         85  86   87   88   89  90                                           __________________________________________________________________________     Diisocyanate                                                                              HMDI                                                                               HMDI HMDI IPDI IPDI                                                                               IPDI                                         Amount (g) 65.5                                                                               131.0                                                                               196.5                                                                               55.6 111.1                                                                              166.7                                                   TMXDI                                                                              TMXDI                                                                               TMXDI                                                                               TMXDI                                                                               TMXDI                                                                              TMXDI                                                   183.0                                                                              122.0                                                                               61.0 183.0                                                                               122.0                                                                              61.0                                         Acid anhydride                                                                            Phtha-                                                                             Phtha-                                                                              Phtha-                                                                              Phtha-                                                                              Phtha-                                                                             Phtha-                                       Amount (g) lic lic  lic  lic  lic lic                                                     anhy-                                                                              anhy-                                                                               anhy-                                                                               anhy-                                                                               anhy-                                                                              anhy-                                                   dride                                                                              dride                                                                               dride                                                                               dride                                                                               dride                                                                              dride                                                   32.9                                                                               32.9 32.9 32.9 32.9                                                                               32.9                                         Catalyst amount (g)                                                                       3.7 3.8  3.9  3.6  3.5 3.4                                          Reaction time (hr)                                                                        28  24   19   30   25  20                                           Polymerization degree                                                                     9   9    9    9    9   9                                            __________________________________________________________________________

                  TABLE 32                                                         ______________________________________                                         Synthesis Example                                                                              90        91       92                                          ______________________________________                                         Diisocyanate    HMDI      HMDI     HMDI                                        Amount (g)      65.5      131.0    196.5                                                       IPDI      IPDI     IPDI                                                        166.7     111.1    55.6                                        Acid anhydride  Phtha-    Phtha-   Phtha-                                      Amount (g)      lic       lic      lic                                                         anhy-     anhy-    anhy-                                                       dride     dride    dride                                                       32.9      32.9     32.9                                        Catalyst amount (g)                                                                            3.5       3.6      3.8                                         Reaction time (hr)                                                                             21        20       20                                          Polymerization degree                                                                          9         9        9                                           ______________________________________                                    

EXAMPLE 5

A polybutylene terephthalate [PBT] manufactured by DAINIPPON INK & CHEMICALS, INC. (Product No. BT-1000) and 1% by weight of the present hydrolysis stabilizer for an ester group-containing resin comprising as the main component one of the carbodiimides obtained in Synthesis Examples 31 to 92 were melt-kneaded using a twin screw extruder and then injection molded into JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength was measured by a tensile tester every time shown in Tables 33 to 38. The results are shown in Tables 33 to 38.

                                      TABLE 33                                     __________________________________________________________________________     t/day                                                                              31 32 33 34 35 36  37 38 39 40 41                                          __________________________________________________________________________     0   610                                                                               620                                                                               620                                                                               610                                                                               620                                                                               620 620                                                                               620                                                                               620                                                                               620                                                                               620                                         10  540                                                                               550                                                                               540                                                                               540                                                                               530                                                                               530 540                                                                               530                                                                               520                                                                               570                                                                               580                                         15  410                                                                               420                                                                               420                                                                               420                                                                               430                                                                               420 430                                                                               420                                                                               430                                                                               450                                                                               460                                         20  230                                                                               240                                                                               230                                                                               250                                                                               240                                                                               240 230                                                                               230                                                                               240                                                                               250                                                                               260                                         30  180                                                                               170                                                                               180                                                                               170                                                                               170                                                                               180 180                                                                               180                                                                               170                                                                               180                                                                               190                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 34                                     __________________________________________________________________________     t/day                                                                              42 43 44 45 46 47  48 49 50 51 52                                          __________________________________________________________________________     0   610                                                                               610                                                                               610                                                                               610                                                                               620                                                                               610 620                                                                               610                                                                               610                                                                               620                                                                               610                                         10  580                                                                               590                                                                               570                                                                               580                                                                               570                                                                               590 590                                                                               530                                                                               560                                                                               540                                                                               540                                         15  470                                                                               470                                                                               480                                                                               470                                                                               460                                                                               470 480                                                                               430                                                                               440                                                                               420                                                                               420                                         20  270                                                                               270                                                                               460                                                                               270                                                                               250                                                                               270 280                                                                               240                                                                               250                                                                               250                                                                               240                                         30  190                                                                               180                                                                               190                                                                               200                                                                               190                                                                               180 180                                                                               170                                                                               180                                                                               180                                                                               170                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 35                                     __________________________________________________________________________     t/day                                                                              53 54 55 56 57 58  59 60 61 62 63                                          __________________________________________________________________________     0   610                                                                               620                                                                               610                                                                               620                                                                               610                                                                               610 610                                                                               610                                                                               620                                                                               610                                                                               610                                         10  560                                                                               540                                                                               530                                                                               540                                                                               560                                                                               560 570                                                                               580                                                                               570                                                                               590                                                                               590                                         15  440                                                                               420                                                                               450                                                                               450                                                                               440                                                                               470 480                                                                               470                                                                               460                                                                               470                                                                               470                                         20  250                                                                               250                                                                               240                                                                               240                                                                               230                                                                               270 260                                                                               270                                                                               250                                                                               270                                                                               270                                         30  180                                                                               180                                                                               180                                                                               170                                                                               170                                                                               180 190                                                                               200                                                                               190                                                                               180                                                                               180                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 36                                     __________________________________________________________________________     t/day                                                                              64 65 66 67 68 69  70 71 72 73 74                                          __________________________________________________________________________     0   610                                                                               610                                                                               610                                                                               620                                                                               610                                                                               620 610                                                                               610                                                                               620                                                                               610                                                                               620                                         10  570                                                                               680                                                                               570                                                                               540                                                                               530                                                                               540 560                                                                               590                                                                               540                                                                               530                                                                               540                                         15  480                                                                               470                                                                               480                                                                               420                                                                               450                                                                               450 440                                                                               470                                                                               420                                                                               450                                                                               450                                         20  260                                                                               260                                                                               260                                                                               250                                                                               240                                                                               240 230                                                                               270                                                                               250                                                                               240                                                                               240                                         30  190                                                                               180                                                                               190                                                                               180                                                                               180                                                                               170 170                                                                               180                                                                               180                                                                               180                                                                               170                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 37                                     __________________________________________________________________________     t/day                                                                              75 76 77 78 79 80  81 82 83 84 85                                          __________________________________________________________________________     0   610                                                                               600                                                                               610                                                                               610                                                                               600                                                                               610 600                                                                               610                                                                               600                                                                               610                                                                               600                                         10  570                                                                               520                                                                               520                                                                               530                                                                               530                                                                               530 520                                                                               530                                                                               520                                                                               520                                                                               530                                         15  470                                                                               420                                                                               430                                                                               430                                                                               440                                                                               430 430                                                                               420                                                                               430                                                                               430                                                                               430                                         20  250                                                                               220                                                                               230                                                                               210                                                                               220                                                                               230 230                                                                               240                                                                               230                                                                               230                                                                               230                                         30  180                                                                               130                                                                               140                                                                               130                                                                               140                                                                               150 150                                                                               130                                                                               140                                                                               140                                                                               140                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                  TABLE 38                                                         ______________________________________                                         t/day 86      87      88    89    90   91   92                                 ______________________________________                                         0     610     600     610   610   610  610  610                                10    530     530     520   530   530  520  520                                15    440     430     430   440   430  430  440                                20    220     230     230   220   230  230  240                                30    140     150     150   140   150  150  150                                                                            (Kg/cm.sup.2)                      ______________________________________                                    

EXAMPLE 6

To a urethane elastomer manufactured by Nisshinbo Industries Inc. product No. F-30) was added 1% by weight of the present hydrolisis stabilizer for an ester group-containing resin comprising as the main component one of the carbodiimides obntained in Synthesis Examples 31 to 92 and then the resulting mixture was formed into a film by a cast method, after which the film was punched to obtain JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength was measured by a tensile tester every time shown in Tables 39 to 44. The results are shown in Tables 39 to 44.

                                      TABLE 39                                     __________________________________________________________________________     t/day                                                                              31 32 33 34 35 36  37 38 39 40 41                                          __________________________________________________________________________     0   890                                                                               890                                                                               880                                                                               880                                                                               870                                                                               880 890                                                                               880                                                                               890                                                                               890                                                                               880                                         3   650                                                                               640                                                                               650                                                                               670                                                                               650                                                                               640 650                                                                               640                                                                               650                                                                               710                                                                               700                                         7   580                                                                               590                                                                               590                                                                               580                                                                               600                                                                               590 580                                                                               590                                                                               580                                                                               600                                                                               600                                         10  530                                                                               530                                                                               540                                                                               530                                                                               520                                                                               520 510                                                                               520                                                                               520                                                                               530                                                                               510                                         15  180                                                                               170                                                                               160                                                                               150                                                                               160                                                                               170 160                                                                               150                                                                               140                                                                               200                                                                               210                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 40                                     __________________________________________________________________________     t/day                                                                              42 43 44 45 46 47  48 49 50 51 52                                          __________________________________________________________________________     0   870                                                                               870                                                                               870                                                                               860                                                                               870                                                                               860 880                                                                               870                                                                               870                                                                               870                                                                               880                                         3   680                                                                               690                                                                               670                                                                               680                                                                               690                                                                               700 680                                                                               650                                                                               640                                                                               650                                                                               650                                         7   600                                                                               590                                                                               580                                                                               570                                                                               580                                                                               590 580                                                                               600                                                                               590                                                                               580                                                                               590                                         10  510                                                                               510                                                                               500                                                                               480                                                                               500                                                                               500 490                                                                               520                                                                               520                                                                               510                                                                               540                                         15  210                                                                               190                                                                               200                                                                               210                                                                               200                                                                               210 200                                                                               160                                                                               170                                                                               160                                                                               160                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 41                                     __________________________________________________________________________     t/day                                                                              53 54 55 56 57 58  59 60 61 62 63                                          __________________________________________________________________________     0   870                                                                               880                                                                               890                                                                               880                                                                               890                                                                               870 870                                                                               870                                                                               870                                                                               860                                                                               870                                         3   640                                                                               650                                                                               670                                                                               650                                                                               650                                                                               670 680                                                                               690                                                                               670                                                                               680                                                                               690                                         7   590                                                                               580                                                                               590                                                                               600                                                                               590                                                                               580 600                                                                               590                                                                               580                                                                               570                                                                               580                                         10  520                                                                               510                                                                               520                                                                               520                                                                               540                                                                               500 510                                                                               510                                                                               500                                                                               480                                                                               500                                         15  170                                                                               160                                                                               150                                                                               160                                                                               170                                                                               200 210                                                                               190                                                                               200                                                                               210                                                                               200                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 42                                     __________________________________________________________________________     t/day                                                                              64 65 66 67 68 69  70 71 72 73 74                                          __________________________________________________________________________     0   860                                                                               860                                                                               890                                                                               870                                                                               860                                                                               890 890                                                                               880                                                                               890                                                                               890                                                                               890                                         3   700                                                                               680                                                                               650                                                                               670                                                                               680                                                                               650 650                                                                               650                                                                               670                                                                               650                                                                               650                                         7   590                                                                               570                                                                               590                                                                               600                                                                               580                                                                               590 590                                                                               580                                                                               590                                                                               590                                                                               590                                         10  500                                                                               489                                                                               540                                                                               490                                                                               500                                                                               540 540                                                                               510                                                                               520                                                                               540                                                                               540                                         15  210                                                                               210                                                                               170                                                                               170                                                                               180                                                                               170 170                                                                               160                                                                               150                                                                               180                                                                               170                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 43                                     __________________________________________________________________________     t/day                                                                              75 76 77 78 79 80  81 82 83 84 85                                          __________________________________________________________________________     0   860                                                                               860                                                                               890                                                                               870                                                                               860                                                                               890 880                                                                               890                                                                               870                                                                               860                                                                               890                                         3   680                                                                               680                                                                               650                                                                               670                                                                               680                                                                               650 650                                                                               650                                                                               670                                                                               680                                                                               650                                         7   580                                                                               570                                                                               590                                                                               600                                                                               580                                                                               590 580                                                                               590                                                                               600                                                                               580                                                                               590                                         10  500                                                                               480                                                                               540                                                                               490                                                                               500                                                                               540 510                                                                               540                                                                               490                                                                               500                                                                               540                                         15  180                                                                               210                                                                               170                                                                               170                                                                               180                                                                               170 160                                                                               170                                                                               170                                                                               180                                                                               170                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                  TABLE 44                                                         ______________________________________                                         t/day 86      87      88    89    90   91   92                                 ______________________________________                                         0     860     890     890   870   860  890  890                                3     680     650     650   670   680  650  650                                7     570     590     590   600   580  590  590                                10    480     540     540   490   500  540  540                                15    210     170     170   170   180  170  170                                                                            (Kg/cm.sup.2)                      ______________________________________                                    

EXAMPLE 7

To a polybutylene terephthalate [PBT] elastomer manufactured by DAINIPPON INK & CHEMICALS, INC. (Product No. GRILUX [registered trademark] EH-700) was added 0.5% by weight of the present hydrolysis stabilizer for an ester group-containing resin comprising as the main component one of the carbodiimides obtained in Synthesis Examples 31 to 92 and the resulting mixture was melt-mixed and extruded using a twin screw extruder and then formed into a film of about 500 μm using a T-die, after which the film thus obtained was injection molded to obtain JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength was measured by a tensile tester every time shown in Tables 45 to 50. The results are shown in Tables 45 to 50.

                                      TABLE 45                                     __________________________________________________________________________     t/day                                                                              31 32 33 34 35 36  37 38 39 40 41                                          __________________________________________________________________________     0   350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               350                                                                               350                                                                               350                                         5   340                                                                               340                                                                               350                                                                               340                                                                               350                                                                               340 340                                                                               340                                                                               340                                                                               350                                                                               350                                         10  330                                                                               340                                                                               340                                                                               340                                                                               340                                                                               330 330                                                                               330                                                                               330                                                                               340                                                                               340                                         20  320                                                                               330                                                                               320                                                                               330                                                                               320                                                                               320 320                                                                               320                                                                               320                                                                               340                                                                               340                                         30  310                                                                               320                                                                               310                                                                               320                                                                               310                                                                               310 310                                                                               310                                                                               310                                                                               330                                                                               330                                         (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 46                                     __________________________________________________________________________     t/day                                                                              42 43 44 45 46 47 48  49 50 51  52                                         __________________________________________________________________________     0   350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               350 350                                        5   350                                                                               340                                                                               350                                                                               340                                                                               340                                                                               340                                                                               340 350                                                                               350                                                                               350 350                                        10  340                                                                               330                                                                               340                                                                               330                                                                               340                                                                               340                                                                               330 340                                                                               340                                                                               340 340                                        20  330                                                                               320                                                                               330                                                                               320                                                                               330                                                                               340                                                                               320 330                                                                               330                                                                               330 330                                        30  330                                                                               310                                                                               330                                                                               320                                                                               320                                                                               330                                                                               310 320                                                                               320                                                                               320 320                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 47                                     __________________________________________________________________________     t/day                                                                              53 54 55 56 57 58 59  60 61 62  63                                         __________________________________________________________________________     0   350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               350 350                                        5   340                                                                               350                                                                               340                                                                               350                                                                               340                                                                               340                                                                               340 340                                                                               350                                                                               350 350                                        10  330                                                                               340                                                                               330                                                                               340                                                                               340                                                                               330                                                                               330 330                                                                               340                                                                               340 340                                        20  320                                                                               330                                                                               320                                                                               330                                                                               330                                                                               320                                                                               330 320                                                                               330                                                                               330 330                                        30  310                                                                               320                                                                               310                                                                               320                                                                               320                                                                               310                                                                               310 310                                                                               320                                                                               320 320                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 48                                     __________________________________________________________________________     t/day                                                                              64 65 66 67 68 69 70  71 72 73  74                                         __________________________________________________________________________     0   350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               350 350                                        5   340                                                                               340                                                                               340                                                                               340                                                                               340                                                                               340                                                                               340 340                                                                               340                                                                               340 340                                        10  330                                                                               340                                                                               340                                                                               340                                                                               330                                                                               330                                                                               330 340                                                                               340                                                                               330 340                                        20  320                                                                               330                                                                               340                                                                               330                                                                               330                                                                               320                                                                               320 330                                                                               330                                                                               330 330                                        30  320                                                                               320                                                                               330                                                                               330                                                                               310                                                                               310                                                                               300 310                                                                               320                                                                               310 320                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 49                                     __________________________________________________________________________     t/day                                                                              75 76 77 78 79 80 81  82 83 84  85                                         __________________________________________________________________________     0   350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350                                                                               350 350                                                                               350                                                                               350 350                                        5   340                                                                               340                                                                               350                                                                               340                                                                               340                                                                               340                                                                               340 350                                                                               350                                                                               340 340                                        10  330                                                                               330                                                                               340                                                                               340                                                                               330                                                                               330                                                                               330 340                                                                               340                                                                               340 330                                        20  330                                                                               320                                                                               330                                                                               330                                                                               320                                                                               330                                                                               320 330                                                                               330                                                                               330 320                                        30  320                                                                               310                                                                               320                                                                               320                                                                               310                                                                               310                                                                               310 320                                                                               320                                                                               320 310                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                  TABLE 50                                                         ______________________________________                                         t/day 86      87      88    89    90   91   92                                 ______________________________________                                         0     350     350     350   350   350  350  350                                5     340     350     340   340   340  340  350                                10    330     340     340   330   330  330  340                                20    320     330     330   320   330  320  330                                30    310     320     320   310   310  310  320                                                                            (Kg/cm.sup.2)                      ______________________________________                                    

EXAMPLE 8

A polyethylene terephthalate [PET] resin manufactured by KANEBO LTD. (Product No. EFG-7) and 0.5% by weight of the present hydrolysis stabilizer for an ester group-containing resin comprising as the main component one of the carbodiimides obtained in Synthesis Examples 31 to 92 were melt-mixed and extruded using a twin screw extruder and then formed into a film of about 500 μm using a T-die, after which the film thus obtained was injection molded to obtain JIS-K6301 Dumbbell No. 4. The sample thus obtained was immersed in hot water at 95° C. and the tensile strength was measured by a tensile tester every time shown in Tables 51 to 56. The results are shown in Tables 51 to 56.

                                      TABLE 51                                     __________________________________________________________________________     t/day                                                                              31 32 33 34 35 36 37  38 39 40  41                                         __________________________________________________________________________     0   630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630 630                                                                               630                                                                               630 630                                        10  650                                                                               640                                                                               650                                                                               650                                                                               640                                                                               650                                                                               650 650                                                                               640                                                                               640 650                                        30  650                                                                               650                                                                               640                                                                               650                                                                               650                                                                               650                                                                               640 640                                                                               640                                                                               650 650                                        60  620                                                                               620                                                                               640                                                                               620                                                                               620                                                                               630                                                                               640 630                                                                               630                                                                               640 640                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 52                                     __________________________________________________________________________     t/day                                                                              42 43 44 45 46 47 48  49 50 51  52                                         __________________________________________________________________________     0   630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630 630                                                                               630                                                                               630 630                                        10  650                                                                               650                                                                               640                                                                               650                                                                               650                                                                               650                                                                               650 650                                                                               640                                                                               650 650                                        30  640                                                                               650                                                                               650                                                                               650                                                                               640                                                                               650                                                                               650 650                                                                               640                                                                               640 650                                        60  630                                                                               630                                                                               640                                                                               640                                                                               630                                                                               640                                                                               630 640                                                                               620                                                                               610 610                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 53                                     __________________________________________________________________________     t/day                                                                              53 54 55 56 57 58 59  60 61 62  63                                         __________________________________________________________________________     0   630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630 630                                                                               630                                                                               630 630                                        10  640                                                                               640                                                                               650                                                                               650                                                                               650                                                                               650                                                                               640 650                                                                               650                                                                               650 650                                        30  650                                                                               640                                                                               650                                                                               650                                                                               650                                                                               640                                                                               650 650                                                                               650                                                                               640 640                                        60  630                                                                               620                                                                               620                                                                               630                                                                               620                                                                               610                                                                               610 620                                                                               610                                                                               610 610                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 54                                     __________________________________________________________________________     t/day                                                                              64 65 66 67 68 69 70  71 72 73  74                                         __________________________________________________________________________     0   630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630 630                                                                               630                                                                               630 630                                        10  640                                                                               640                                                                               640                                                                               650                                                                               650                                                                               640                                                                               650 650                                                                               650                                                                               650 650                                        30  640                                                                               650                                                                               650                                                                               650                                                                               650                                                                               640                                                                               650 650                                                                               650                                                                               650 650                                        60  640                                                                               630                                                                               640                                                                               610                                                                               610                                                                               600                                                                               610 610                                                                               630                                                                               610 620                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                                      TABLE 55                                     __________________________________________________________________________     t/day                                                                              75 76 77 78 79 80 81  82 83 84  85                                         __________________________________________________________________________     0   630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630                                                                               630 630                                                                               630                                                                               630 630                                        10  650                                                                               640                                                                               640                                                                               650                                                                               650                                                                               640                                                                               650 650                                                                               650                                                                               640 650                                        30  640                                                                               650                                                                               650                                                                               650                                                                               650                                                                               640                                                                               650 650                                                                               650                                                                               640 650                                        60  610                                                                               630                                                                               640                                                                               610                                                                               610                                                                               600                                                                               610 610                                                                               610                                                                               600 610                                        (Kg/cm.sup.2)                                                                  __________________________________________________________________________

                  TABLE 56                                                         ______________________________________                                         t/day 86      87      88    89    90   91   92                                 ______________________________________                                         0     630     630     630   630   630  630  630                                10    640     650     650   640   650  650  650                                30    650     650     650   640   650  650  650                                60    640     610     610   600   610  610  610                                                                            (Kg/cm.sup.2)                      ______________________________________                                    

As described above, the present hydrolysis stabilizer for an ester-containing resin has an excellent compatibility with the ester group-containing resin and can be added to the resin without causing any trouble when the resin was synthesized and melt-kneaded. Moreover, since the hydrolysis stabilizer has a high molecular weight, it can sufficiently exhibit the hydrolysis stabilizing effect on the resin.

The present process for the hydrolysis stabilization of an ester group-containing resin comprises mixing the above-mentioned hydrolysis stabilizer with the ester group-containing resin, and hence, can be easily carried out. 

What is claimed is:
 1. A composition comprising an ester group-containing resin and a carbodiimide having at least two carbodiimide groups in the molecule and prepared by the carbodiimidization of 4,4'-dicyclohexylmethane duisocyanate represented by the formula (I): ##STR7## or isophorone diisocyanate represented by the formula (II): ##STR8## or a mixture of 4,4'-dicyclohexylmethane diisocyanate of the formula (I) and isophorone diisocyanate of the formula (II) wherein the composition is stabilized against hydrolysis.
 2. A composition stabilized against hydrolysis according to claim 1, wherein the carbodiimide is end-blocked with a primary or secondary amine, a carboxylic acid, an acid anhydride or a monoisocyanate.
 3. A composition stabilized against hydrolysis according to claim 1, wherein the carbodiimide has an average degree of polymerization of 2 to
 30. 4. A composition comprising an ester group-containing resin and a carbodiimide having at least two carbodiimide groups in the molecule and prepared by the carbodiimization of a mixture of tetramethylxylylene diisocyanate represented by the formula (III): ##STR9## with 4,4'-dicyclohexylmethane diisocyanate represented by the formula (I): ##STR10## or isophorone diisocyanate represented by the formula (II): ##STR11## or wherein the carbodiimides are prepared by the carbodiimization of a mixture of tetramethylxylylene diisocyanate represented by formula (III) with 4,4'-dicyclohexylmethane diisocyanate represented by formula (I) and isophorone diisocyanate represented by formula (II), and wherein the composition is stabilized against hydrolysis.
 5. A composition stabilized against hydrolysis according to claim 4, wherein the carbodiimide is end-blocked with a primary or secondary amine, a carboxylic acid, an acid anhydride or a monoisocyanate.
 6. A composition stabilized against hydrolysis according to claim 4 wherein the carbodiimide has an average degree of polymerization of 2 to
 30. 